Cryogenic pumping system

ABSTRACT

A PUMPING SYSTEM IS DISCLOSED FOR USE IN ASSOCIATION WITH CRYOGENIC FLUID, TO ACCOMPLISH FLUID FLOW BY UTILIZATION OF THE NEGATIVE ENERGY STORED BY THE CRYOGENIC FLUID. A HEAT EXCHANGE MEANS RECEIVES THE CRYOGENIC FLUID TO GASIFY A QUANTITY THEREOF AND THEREBY DRIVE A TURBINE WHICH IS CONNECTED TO MOTIVATE A PUMP. ONE EMBODIMENT INCLUDES A BURNER TO SUPPLY ADDITIONAL HEAT TO THE HEAT EXCHANGER UPON COMBINATION OF SPENT GAS FROM A TURBINE. IN ANOTHER EMBODIMENT A SECOND HEAT EXCHANGER IS PROVIDED ACROSS THE FLUID INTERFACE OF A CRYOGENIC TANK SO AS TO PRESSURIZE THE TANK. VARIOUS CHECK AND OTHER VALVES ARE ALSO INCORPORATED IN THE EMBODIMENTS DISCLOSED FOR CONTROLLING THE FLOW OF THE FLUID.

March .1971 E. H. SCHWARTZMAN 3,570,261

CRYOGENIC PUMPING SYSTEM Filed April 14, 1969 BURNER United StatesPatent O 3,570,261 CRYOGENIC PUMPING SYSTEM Everett H. Schwartzman, 724Cloyden Road, Palos Verdes Estates, Calif. 90274 Continuation-impart ofapplication Ser. No. 504,349, Oct. 24, 1965. This application Apr. 14,1969, Ser. No. 815,543

Int. Cl. F17c 7/02 US. Cl. 6253 Claims ABSTRACT OF THE DISCLOSURE Apumping system is disclosed for use in association with cryogenic fluid,to accomplish fluid flow by utilization of the negative energy stored bythe cryogenic fluid. A heat exchange means receives the cryogenic fluidto gasify a quantity thereof and thereby drive a turbine which isconnected to motivate a pump. One embodiment includes a burner to supplyadditional heat to the heat exchanger upon combination of spent gas froma turbine. In another embodiment a second heat exchanger is providedacross the fluid interface of a cryogenic tank so as to pressurize thetank. Various check and other valves are also incorporated in theembodiments disclosed for controlling the flow of the fluid.

This application is a continuation-in-part of Ser. No. 504,349, filedOct. 24, 1965, now Patent No. 3,451,342, granted June 24, 1969.

BACKGROUND AND SUMMARY OF THE INVENTION In modern technology, the needsometimes arises to perform mechanical work in an environment whichincludes a reservoir of cryogenic fluid and a source of heat, as theatmosphere or some other mass or body having a non-cryogenictemperature. Typically, the need might arise for a fluid pump in such anenvironment as for transferring the cryogenic fluid from its container.

Considering applications of the present invention in somewhat greaterdetail, the expanded field of cryogenics has resulted in a widespreadneed for pumping systems to transport cryogenic fluid. For example, theneed for a pumping system arises in the operation of transportationvehicles, pipelines, storage tanks and so on. In the past, it has beensomewhat conventional to employ conventional pumping systems, e.g. anelectric motor and fluid pump combination, in these applications.However, such conventional pumping systems are relatively expensive andrequire an integral electrical system or other auxiliary power source.Consequently, a considerable need exists for an effective, inexpensiveand safe pumping system for transporting fluid in systems utilizingcryogenic fluid.

In general, the present invention comprises a simple pumping systemwhich utilizes the negative energy of cryogenic fluid to power a turbinewhich is in turn mechanically coupled to a pump. The system incorporatesheat exchangers and valves to afford the requisite control.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, which constitutes apart of this specification, an exemplary embodiment demonstratingvarious objectives and features hereof is set forth as follows:

FIG. 1 is a schematic diagram illustrating a pumping system constructedin accordance with the present invention;

FIG. 2 is a schematic diagram illustrating an alternative embodiment ofa pumping system incorporating the present invention; and

Patented Mar. 16, 1971 "ice DETAILED DESCRIPTION OF THE ILLUSTRATIVEEMBODIMENT Referring initially to FIG. 1, there is shown a source 10 ofcryogenic fluid which may comprise a tank, a pipe, or virtualy anysource for providing a stream of cryogenic fluid. The source 10 isconnected through a duct 12 to a pumping system 14. It is to be noted,that the pumping system 14 is provided energy by utilization of thecryogenic fluid flowing therethrough. In this regard, the pumping system14 utilizes the negative energy of a cryogenic fluid then burns thespent cryogenic fluid to provide additional energy.

Considering the system 14 in greater detail, the duct 12 is coupledthrough a pump 17 (impeller or the like) to a duct 18 which is in turnconnected through a heat exchanger 20 to a turbine 22. The dischargefrom the turbine 22 is to a duct 24 which is in turn connected to aburner 26 positioned in the proximity of the heat exchanger 20 and to asupply line 25.

The system of FIG. 1 is well suited to provide gaseous fuel (naturalgas) to a distribution system (through line 25) from a cryogenic tank(source 10). In such an application, the system accomplishes the dualpurposes of gasi fying the fluid and delivering it at an elevateddistribution pressure. Generally the system accomplishes these changeswithout external power because the negative energy of the cryogenicfluid is used. Such an operation involves the pump accomplishing apressure that is greater than desired, so that the gas emerges in theline 25 at the desired pressure.

The heat exchanger 20 and the turbine 22 as well as the burner 26 maytake a variety of well known forms of such elements. Specifically, forexample, the turbine 22 may comprise a rotary high speed gas turbine,the drive shaft of which is connected to the pump by a mechanicallinkage as indicated by the dashed line 28.

In the operation of the system as shown in FIG. 1, some external forcesmay be required for starting. For example, it may be necessary to drivethe pump 17 externally in some systems until the operation isestablished. At that time, the pump 17 draws cryogenic fluid from thesource 10 supplying a stream to the heat exchanger 20. The heatexchanger gasifies the cryogenic fluid as a result of exposure toambient temperature as well as heat which may be drawn from the burner26. Thus, gas at a substantial pressure is developed which is utilizedto drive the turbine 22. The rotational drive of the turbine 22 iscoupled to drive the pump 17, as indicated above through a mechanicalcoupling indicated by the line 28. The fluid from the turbine 22 (atelevated pressure) then flows to the burner 26 for combustion and to thedistribution pipe or line 25. In this regard, the burner 26 may becontrolled or even eliminated from the system in some applications inwhich ambient temperature is relied upon to gasify the cryogenic fluid.However, in the system as disclosed in FIG. 1, the burner affords aneflicient means of utilizing gas from the turbine 22.

In the utilization of the negative energy of the cryogenic fluid, it isto be appreciated that the considerable negative temperature of thefluid results in a rapid heating thereof within the heat exchanger 20.Of course, as energy (heat) is drawn into the cryogenic fluid, itreaches the temperature of vaporization and is consequently gasified todrive the turbine 22. Of course, the utilization of the burner 26 in thesystem presumes that the cryogenic fluid is combustible, e.g. naturalgas.

In the specific application for the system of FIG. 1, a pipeline is alsoapplicable. That is, the duct 12 and the outlet line 25 may be portionsof a pipeline through which liquid natural gas is to pass. The insertionof the pumping system 14 then results in the effective gasification ofthe cryogenic fluid as well as pressurization to flow through thepipeline. The system thus will accomplish an eflicient, convenient, andeconomical delivery structure, which does not require auxiliary powerapparatus or supply means.

As suggested above, the system hereof may take a variety of differentforms, and may be integrated with various cryogenic structures. Forexample, FIG. 2 shows a system incorporating the principles of thepresent invention for use in conjunction with a storage tank 30containing cryogenic fluid 32. The tank 30 may comprise a relativelylow-pressure vessel with the result that auxiliary pumping means isrequired to expedite the flow of fluid therefrom. However, to supplementthe operation of the pumping means, a structure is provided foraccomplishing a limited pressure within the tank 30. Specifically, theoutlet 34 from the tank is connected through a valve 36 and a heatexchanger 38 to a duct 40 that is returned to the top of the tank 30.Consequently, the heat exchanger 38 is coupled across the liquid-gasinterface 42 defined within the tank 30. As a consequence, upon openingthe valve 36, fluid is passed to the heat exchanger 38 to be gasified byambient temperature. Upon gasification of the cryogenic fluid, itdevelops a pressure which is applied through the duct 40 to theinterface 42 thereby forcing the cryogenic fluid 32 from the outlet 34more effectively.

The main stream of cryogenic fluid flowing through the outlet 34 issupplied through a pump 44 to a discharge duct 46. A small stream offluid is passed from. the discharge duct 46 to a heat exchanger 48wherein such fluid is gasified to drive a turbine '50. The spent fluidfrom the turbine 50 is discharged through a duct 52 and the rotaryenergy developed by the turbine 50 is coupled to drive the pump 44 asindicated by a dashed line 54. Consequently, the pump 44 effectivelyforces cryogenic fluid through the duct 46 in an efficient andconvenient delivery operation.

In the system of FIG. 2, some initial starting forces may be necessaryto initiate a delivery operation. However, alternatively, control may beaccomplished simply by opening the valve 36. That is, systems may bedesigned which utilize an open pump 44 so that upon opening the valve 36sufficient cryogenic fluid is provided to the heat exchanger 48 toinitiate a boot strap operation which will promptly bring the system topeak operation. As shown, a burner 49 (similar to the burner 26 ofFIG. 1) is provided contiguous to the heat exchanger 48 to receive aportion of the discharge from the turbine 50 to supply heat to the heatexchanger 48.

The system of FIG. 2 may be effectively employed in cooperation withtanker trucks, stationary tanks or various other structures utilizing atank to contain a reservoir of cryogenic fluid from which deliveries areto be made.

Referring now to FIG. 3, there is shown another embodiment of a pumpingsystem incorporating the present invention and including a tank 160,which comprises a vessel capable of containing substantial pressure. Thetank 60 contains cryogenic fluid in a liquid phase 62 and a gaseousphase 64, the two being separated by an interface 66. The liquid phaseof the cryogenic fluid is coupled to an outlet 68 which is in turncoupled to a main-stream duct 70 and a lesser stream duct 72 including avalve 74. The duct 72 is connected through a heat exchanger 76 and aduct 78 to re-enter the vessel or tank 60 at the gaseous phase 64. Theduct 78 is also connected through a valve 80 and a heat exchanger 82 toa turbine 84 having an exhaust duct 86 for spent cryogenic fluid.

The main stream for cryogenic fluid passing from the tank 60 through theduct 70 is propelled by a pump 88 which is coupled to a system outlet90. The pump is also connected to provide a small stream through a duct92 and a valve 94 back to the heat exchanger 76. Consequently, the heatexchanger 76' receives cryogenic fluid through both the valves 74 and94.

In general, in the operation of the system of FIG. 3, the cryogenicfluid undergoes two stages of gasification. The first stage ofgasification is accomplished in the heat exchanger 76 and serves topressurize the tank 60 as well as to supply fluid to the heat exchanger82 for further gasification resulting in pressure fluid for driving theturbine 84. As in the embodiments described above, the turbine isconnected to drive the pump, specifically, turbine 84 is connected tothe pump 88 as indicated by the dashed line 92.

In the operation of the system, the valve 74 may be opened preliminarilyto supply a small quantity of fluid to the heat exchanger 76 which isgasified by heat from ambient and thereby pressurizes the tank as aresult of re-entry into the gaseous phase 64. Upon opening the valve 80,cryogenic fluid is permitted to flow to the heat exchanger 82 forfurther gasification by ambient heat to thereby drive the turbine 84. Asthe turbine 84 is actuated, the pump 88 is driven to provide the mainflow stream through the duct 90. Upon opening the valve 94, a portion ofthat stream is supplied back to the heat exchanger 76 to affordincreased cryogenic fluid which establishes the system at a peak ofoperation.

A consideration of the above in conjunction with the theoreticalconsiderations set forth in the above-referenced co-pending case byapplicant indicates that a selfcontained system is provided toeffectively pump fluid without the requirement of a supply from anauxiliary power source. The system is effective, economical and verypractical.

What is claimed is:

1. A pumping system for providing cryogenic fluid fuel at an elevatedpressure, comprising:

a source means for providing cryogenic fluid fuel;

heat-exchange means connected to receive said cryogenic fluid fuel fromsaid source means and for receiving heat to thereby gasify a quantity ofsaid fluid fuel;

a turbine means connected to said heat-exchange means to receivegasified fluid fuel from said heat-exchange means and be powered therebyto provide drive power;

a pump means coupled to said turbine means whereby to elevate thepressure of fluid fuel from said source and to thereby pump said fuel;and

a burner means connected to receive a portion of said fluid fuelexhausted from said turbine means, said burner means being aflixed tosupply heat to said heat-exchange means.

2. A pumping system according to claim 1 wherein said source meanscomprises a fluid container for storing a quantity of said cryogenicfluid fuel.

3. A pumping system according to claim 2, further including a secondheat-exchange means, and means for connecting said second heat-exchangemeans around the phase interface of fluid in said container.

4. A pumping system according to claim 1, further including a valvemeans coupled to control the flow of cryogenic fluid from said sourcemeans.

5. A pumping system according to claim 1, wherein said source meanscomprises a fluid container for storing a quantity of said cryogenicfluid fuel, further including a second heat-exchange means, and meansfor connecting said second heat-exchange means around the phaseinterface of fluid in said container and further including a valve meanscoupled to control the flow of cryogenic fluid from said source means.

(References on following page) References Cited UNITED STATES PATENTSMartin 62-50 Martin 6250X Morrison 6250 Bocquet et a1. 6252 Kashohn eta1 6250X Robinson et a1 60-36 Thompson 62-53 Wildhack 02-5324 6Spaulding 6252X Webster 6253X Rendos et a1 62--52 Bell et a1. 6253XKrigsman 6252X US. Cl. X.R.

